Galvanoplastic multiplication of sound record bands



P 29, H. WESTERKAMP 2,297,271

GALVANOPLASTIC MULTIPLICATION OF SOUND RECORD BANDS Filed May 9, 1959- Inventor:

Patented Sept. 29, 1942 OFFICE."

GALVANOPLASTIO MuLTIrLIoATIoN oFv SOUND. RECORD BANDS ,Hugo Westerkamp, Cologne-Braunsfeld, Germany; vested in theAlien Property-Custodian Application May 9, 1939, Serial Nb; 272,6 In Germany May 6, 1938 1 Claim.

The invention relates to a process and an apparatus for the galvanoplastic multiplication of sound record bands with mechanical sound inscription, in particular of sound record bands which consist of a carrier in band form with a layer of wax in which the sound records are cut by mechanical sound inscription as sound tracks.

In the multiplication of such sound record bands in the manner known for example with sound record plates by the recorded surface of the wax layer being made electrically conductive by cathode atomisation, graphiting or by chemical means, and the band being then placed in a galvanic bath in which by electrolytic deposition there is deposited on the conductive surface of the wax layer a layer which after detachment from the original record band, is used for obtaining copies by pressure of the original record band, great difiiculties have been met with which are to be attributed to the band form of the original carrier and the excessive sensitiveness of the layer of wax having on it the sound inscription. As each contact with the sound inscription affects the sound record, it is necessary to keep the original record band, the length of which as a rule amounts to many meters, in the stretched condition until the galvanic process is terminated.

The object of the invention is to obviate these disadvantages, to facilitate the manipulation of the original band and at the same time to permit the production of the master band in the smallest possible space. This is attained by the original record band being made conductive on its recorded surface, together with a band serving as anode being wound into a flat spiral in which the adjacent edges lie substantially in a plane, and with the interposing of distance pieces on the recorded surface of the original record band, and placed in the galvanic bath.

Here preferably the width of the anode band is equal or approximately equal to the width of the original record band and the anode band is provided at its edges with distance pieces arranged at intervals. The distance pieces can be formed by ribs stamped out of the edges of the anode band but they can also consist of movable clips on the edges of the anode band.

The process according to the invention and embodiments of the anode band used therein are illustrated on the annexed drawing, in which Figure 1 shows in end view an original record band wound according to the invention together with the anode band,

Figure 2 shows a section on the line 11-11 of Figure 1,

Figure 3 is an elevation of the anode band with distance pieces worked therein,

Figure 4 is a section through an anode band with distance pieces fitted thereon.

The original record band consists as is best seen from Figure 2, of a carrier I, for example a normal film strip, and the wax layer 2. The materials of the band are non-conductive. The sound processes are recorded by mechanical sound inscription as sound tracks or grooves in this wax layer as indicated at 3. The sound inscription covers only the centre part of the record band, whilst the edges of the band are not 'played on.

The played-on surface of the wax layer is made conductive by cathode atomising, graphi-ting or by chemical means, that is, the surface is coated with a skin-thin conductive layer 4. When the anode band 5 has conductive distance pieces 6, this coating extends over the region of the recording but terminates short of the edge portions which are to be engaged by the distance pieces, as shown in Fig. 2.

The band so prepared and of many meters in length is now according to the invention wound together with a band serving as anode with the interposing of distance pieces between the recorded side of the original record band and the anode band, and placed in a galvanic bath. The band serving as anode and consisting for example of copper which is wound together with the original record band is indicated by 5, whilst the distance pieces are indicated by 6. The dis tance pieces are of such width that they only bear against the unrecorded edges of the original record band and the region of the sound recording is left free. When the original record band is wound in the manner described completely with the anode band, it is placed in the galvanic bath and, as shown in Figure 2, is so connected with the current source that the anode band is connected on to the positive pole and the conductive surface of the sound inscription to the negative pole. The original record band then takes up an extremely small space and is easily handled, as the sound inscription is entirely covered and protected from injury.

According to Figures 1-3, the distance pieces 6 are worked out of the anode band 5, and consist of rib-like projections which are stamped at intervals along the edges of the anode band. The distance pieces can, however, also consist of independent parts, for example as shown in Figure 2 4 of clips pushed over the edges of the anode band. In this case, it is particularly easy to make the distance pieces of non-conductive material, whereby the danger is avoided of a direct conductive connection between the anode band and the conductive surface of the original record band.

I claim:

A device for preparation of an electrolytically deposited matrix from which multiple sound record bands may be prepared, comprising sound record and anode bands in the form of aspiral wound about an axis transverse to the lengths of said bands, said bands being of like width, the sound record band having a carrier l'ayer an'da mechanically sensitive wax recording layer with mechanical out sound record grooves located in one longitudinally extending region of the surface thereof and with edge portions of the wax layer free of such grooves, said recorded region having an electrically conductive coating thereon, said anode band being smooth and free of projections over the region of its surface opposite said recorded region and having at its edges projections spaced longitudinally along the anode band and extending toward and. into contact with the said edge portions of the wax layer and holding the anode band spaced from the sensitive wax surface for providing a continuous spiral compartment for. electrolyte and for protecting the region of the recorded wax surface from mechanical contact, said compartment being open to the exterior at the spaces between said pro- 1 jections.

HUGO WESTERKAMP. 

